How Many Solar Panels Do I Need To Go Off-Grid?

Going off-grid means that you completely disconnect your home and its appliances from the national power grid.  

If you have played with the idea of doing this, then I bet you top dollar one of the first questions you have asked yourself was: How many solar panels do I need to go off-grid?

The answer you will soon find, is somewhat complex and solely depends on your own home’s individual energy needs. 

In this article, I aim to take you through the entire solar system requirement process, and by the end of it you will know just how many photovoltaic panels you will need to take your home off-grid. 

What does it mean to go Off-Grid? 

Off-grid living is a characteristic of housing and lifestyle.

The term “off the grid” can be associated with people that decide to disconnect their homes from the national electrical grid.

Today, going off grid is still considered the ultimate path to living rough, but it does not have to be all that serious though.

Off-grid living can also mean people create and utilize their own utilities, like gas, water and electricity generated from solar systems (probably the most popular option).

In general, self-sustainable off grid homes tend to be popular (or rather a necessity) in locations that are more isolated from common governmental utilities like electricity.

However, isolated homes are not the only ones that make use of solar panels to generate their own electricity.

Off-grid living also attracts environmentally conscious, forward thinking individuals who want to reduce their ecological footprint while saving on monthly utility costs.

• In summary, taking your home off-grid means you are able to create/supply energy, drinkable water, grow food and manage waste/wastewater for yourself. You can still use household appliances such as TVs, refrigerators, coffee makers, and vacuum cleaners while off-grid.

Can I Go Off-Grid with Solar Panels? 

When it comes to creating and supplying your own electricity, there is possibly no greener technology more accessible and efficient than solar panels. 

For the most part, going off-grid with solar panels is 100% possible. However, it is just one piece to the puzzle.

In order to maintain a healthy prolonged off the grid lifestyle, you will need some place to store all that solar energy generated by your solar panels. 

And just like solar panels are the most accessible and efficient for electricity production, solar batteries/solar power stations, are the absolute best technology out there to store your off-grid solar energy.

So in essence, you can go off-grid with solar panels and some sort of storage system.

How many solar panels do I need to go off-grid? 

The number of solar panels needed to go off-grid, solely depends on the following factors:

• Amount of electricity you use
• Amount of useable roof space
• Amount of direct daily sunlight 
• The type of solar panel you choose

The average off-grid home usually requires about 7 Kw (or 7000 Watts) of power to rely entirely on its own energy production. 

Solar panels come in various forms, shapes and sizes. Two major factors that determine the amount of solar panels you will need to go off-grid, depends on your energy requirements and the performance output of each panel. 

• Panel performance is rated under standard testing conditions (STC): irradiance of 1,000 W/m², solar spectrum of AM 1.5 and module temperature at 25 °C.

Usually the larger the panel, the higher the panel performance.

For example, a 100-watt solar panel typically measures 47 x 21,3 x 1,4 inches. A 200-Watt solar panel measures 64 x 26 x 1,4 inches (these are rough estimates). 

The bigger the framework, the more photo-voltaic cells are able to be mounted inside of it, thus more performance. 

If your energy requirements were as such as the average mentioned above (7 Kw) and you were to use 200-watt solar panels, then you'd need more or less 35 panels to take your home off-grid. Or if you used 350-watt solar panels, you'd need 20 panels. 

To give you an idea of how much area say 35 solar panels will take up, you will need to find the total square footage. 

In the U.S, the average homes roof is about 1700 square feet. 

• 35 solar panels will take up more or less 389 square feet of your homes roof space. This leaves more than enough room in case you add any extra panels to your system in the future. 

To make things easier for you, we have compiled this chart to give you a basic ballpark on how many solar panels you will need depending on your situation. 

(A 200 Watt solar panel measures roughly 11,13 sq. ft)

How Can I Calculate How Many Solar Panels I Will Need?

There is a somewhat basic formula to help you understand how much solar panels you''ll need to go off-grid and it looks like this. 

Let me break this formula down even further so you can understand how to use it better.  

Step 1 - Figure out how much electricity you use.

Go ahead and grab your most recent power bill and figure out how much energy you used for the last month.

Most energy bills will display the kWh used at the bottom of the document with the cost of electricity multiplied by that. 

In the example below you can see that we used 1000 kWh for that month and were charged $134,35. 

Step 2 - Work out how much sunlight your county receives

In order to know how many solar panels you'll need to go off-grid, you have to figure out how many peak hours of sunlight your area receives. 

Keep in mind though, that peak hours of sunlight do not equal the time between sunrise and sunset. 

Peak hours of sunlight equal the amount of time the sun reaches an average of 1000 Watts per square meter. 

So in summary, peak hours of sunlight equal the amount of time the sun is at its most powerful allowing the solar panels to be at their most productive. 

If you live somewhere like California, an area with a very high peak sunlight rate, your solar system will not need to be as big.

However, if you stay in a less sunny place you may need more solar panels in order to produce the same amount of electricity you would with less panels in a sunnier location. 

(Another important factor to consider is the angling of your roof. The amount of shading it has can also affect the number of solar panels needed.)

You can check the National Renewable Energy Laboratory website to determine how much peak hours of sunlight your area has. 

The table below represents the number of peak sunlight hours in different regions of the United States. 

Step 3 - Calculate the size solar system you need to go off-grid.

Once you know how many hours of peak sunlight your area receives you can figure out what size solar system you'll need. 

To begin you need to figure out how many average peak sunlight hours you get in a month. 

Simply multiply your daily sunlight hours by 30. 

For this example, we will use Florida. So, we multiply 5.44 by 30 to get 163,2. Let's round that off to 163 hours of peak sunlight every month. 

Next, we divide your monthly electricity usage (let's use 1000kWh) by those monthly sunlight areas. 

So, 1000 kWh divided by 163 sunlight hours equals 6.1. This basically means you will need a 6.1 kW solar system in order to produce enough electricity to cover your monthly energy consumption. 

Below I created a chart which shows you the size solar system needed in various states based on the average peak monthly sun hours. 

Step 4 - Calculate how many solar panels you need to go off-grid.

The first thing you need to do is convert the kW solar system into watts and to do this simply multiply the system size by 1000. 

We will once again use Florida: 6,1kW x 1000 = 6,100 Watts.

To figure out how many solar panels you will need you now need to decide on what wattage your solar panel will produce. 

Let's say for example you want to invest in a 200-Watt solar panel system. 

6,100 Watts divided by 200 Watts equals 31. 

This means in Florida you will need 31 solar panels to meet your energy demand of 1000 kWh a month. 

Conclusion

I hope you now understand the whole process behind deciding on the number of solar panels you will need to go off-grid. 

At the end of the day the amount of electricity you use, amount of useable roof space, amount of direct daily sunlight and the type of solar panel are all determining factors on how many solar panels you will need.

If you plan to go camping on a shorter off-grid trip, we recommend you try out a smaller solar panel and power station to keep you juiced up. 

We recommend our 120 Watt solar panel and our new EB70 power station.